Managing Urban Watershed Pathogen Contamination

Transcription

1 EPA/600/R-03/111 September 2003 Managing Urban Watershed Pathogen Contamination by Joyce M. Perdek, Russell D. Arnone, and Mary K. Stinson Water Supply and Water Resources Division Urban Watershed Management Branch Edison, New Jersey and Mary Ellen Tuccillo Oak Ridge Institute of Science and Education Water Supply and Water Resources Division Urban Watershed Management Branch Edison, New Jersey National Risk Management Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268

2 Notice The information in this report has been subjected to Agency peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ii

3 Abstract This document is written as a resource for state and local watershed managers who have the responsibility of managing pathogen contamination in urban watersheds. In addition it can be an information source for members of the public interested in watershed mitigation efforts aimed at reducing microbial contamination. It is written to support specific steps of the total maximum daily load (TMDL) process for meeting water quality standards in urban watersheds. The information provided can also support watershed evaluations conducted when disease outbreaks occur in the absence of standards violations. The document discusses the regulation of waterborne pathogens (Chapter 1), detection methods (Chapter 2), and combined sewer overflow control technologies and stormwater best management practices (Chapter 3). The table below identifies the steps of the TMDL process supported by each of the chapters. The intent is to supplement the information included in the EPA document Protocol for Developing Pathogen TMDLs, Office of Water, January 2001, EPA 841-R guidance. This document was developed using information collected through extensive literature reviews by researchers in the Urban Watershed Management Branch (UWMB) of EPA s National Risk Management Research Laboratory. The final document will be an official EPA report available through the UWMB Internet site Steps of TMDL Process Supported by the Document Chapters Steps of TMDL Process TMDL Step 1: TMDL Step 2: TMDL Step 3: TMDL Step 4: TMDL Step 5: TMDL Step 6: TMDL Step Problem Identification Identification of Water Source Assessment Linkage Between Allocations Follow-up Monitoring 7: Assembling Quality Water Quality and the TMDL Indicators and Targets Evaluation Target Values and Pollutant Sources Document Chapters Chapter 1. Pathogens of Chapter 3. Concern Management and Control of Chapter 2. Detection Methods and Pathogens Alternate Indicator Organisms iii

4 Foreword The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation s land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this mandate, EPA s research program is providing data and technical support for solving environmental problems today and building a science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our health, and prevent or reduce environmental risks in the future. The National Risk Management Research Laboratory (NRMRL) is the Agency s center for investigation of technological and management approaches for preventing and reducing risks from pollution that threaten human health and the environment. The focus of the Laboratory s research program is on methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and subsurface resources; protection of water quality in public water systems; remediation of contaminated sites, sediments and ground water; prevention and control of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that reduce the cost of compliance and to anticipate emerging problems. NRMRL s research provides solutions to environmental problems by: developing and promoting technologies that protect and improve the environment; advancing scientific and engineering information to support regulatory and policy decisions; and providing the technical support and information transfer to ensure implementation of environmental regulations and strategies at the national, state, and community levels. This publication has been produced as part of the Laboratory s strategic long-term research plan. It is published and made available by EPA s Office of Research and Development to assist the user community and to link researchers with their clients. Hugh W. McKinnon, Director National Risk Management Research Laboratory iv

5 Contents Notice.... ii Abstract.... iii Foreword....v List of Tables... ix List of Figures....x Acknowledgments... xi Chapter One Regulating Waterborne Pathogens Introduction Health Effects Waterborne Disease Outbreaks Pathogenic Bacteria of Concern Campylobacter E. Coli O157:H Legionella pneumophilia Leptospira Salmonella Shigella Vibrio cholerae Yersinia entercolitica Pathogenic Protozoa of Concern Cryptosporidium Cyclospora Giardia lamblia Entamoeba histolytica Naegleria fowleri Pathogenic Viruses of Concern Adenoviruses Astroviruses Caliciviruses Enteroviruses Hepatitis A and Hepatitis E Reoviruses Rotaviruses Pathogenic Helminth Worms Nematodes Cestodes v

6 Contents (cont.) Trematodes Pathogenic Fungi Microbial Water Quality Standards Clean Water Act TMDL Description and Definition Stormwater, Combined Sewer Overflow and Sanitary Sewer Overflow Regulations Safe Drinking Water Act State Standards Other Applicable Standards Coastal Zone Act Reauthorization Amendments Beaches Environmental Assessment, Closure, and Health (BEACH) Program Evaluation of Pathogen Indicators Use of Indicators Relationships between Indicators and Illness Conclusions References Chapter Two Detection Methods and Alternate Indicator Organisms Introduction Detection Methods Bacteria Cultural and Enzyme-Based Methods Immunological Methods Genetic Methods (Gene Probes and PCR) Viruses Sample Concentration Cultural Assay Immunological Techniques Gene Probes PCR-based Methods Cryptosporidium and Giardia Immunofluorescence Gene Probes and PCR-Based Methods Alternative Indicator Organisms vi

7 Contents (cont.) Clostridium perfringens Bacteriophages Microbial Source Tracking Antibiotic Resistance Analysis Molecular Methods Conclusions References Chapter Three Management and Control of Pathogens Introduction Disinfection Technologies for Control of Pathogens Introduction WWF Disinfection Effectiveness Requirement for a High-Rate Disinfection Process Requirement for Suspended Solids Removal WWF Disinfection Technologies Chlorination and Dechlorination Ultraviolet Light Irradiation Chlorine Dioxide Ozonation Description of Disinfection Studies and Implementation Examples Disinfection Pilot Study at the 26 th Ward WWTP Testing Facility in New York City Continuous Deflection Separation, Fuzzy Filter and UV Treatment of SSO-Type Wastewaters: Pilot Study Results Advanced Demonstration Facility (ADF) in Columbus, GA Washington, DC. Northeast Boundary Swirl Facility (NEBSF) Birmingham, AL. UV Disinfection at Peak Flow WWTP Oakland County, MI. Chlorine Disinfection at Acacia Park Bremerton, WA. UV Disinfection at CSO Treatment Facility Disinfection of Collected Stormwater and Dry Weather Urban Runoff Best Management Practices (BMPs) for Control of Pathogens in Urban Stormwater Introduction Structural BMPs Ponds and Wetlands vii

8 Contents (cont.) Sand Filters Illicit Discharge Detection and Elimination Nonstructural BMPs Managing Waste from Resident Canada Geese Effects of BMPs on Receiving-Water Quality Conclusions References viii

9 Tables Table 1-1. U.S. Microbial Water Quality Assessments Summary 1999 and Table 1-2. Outbreaks Associated with U.S. Natural Recreational Waters, Table 1-3. Water Treatment Effectiveness on Pathogens Table 1-4. Outbreaks Associated with Drinking Water from U.S. Surface Sources, Table 1-5. Waterborne Bacteria of Concern to Human Health and Their Associated Diseases Table 1-6. Waterborne Protozoans of Concern to Human Health and Their Associated Diseases Table 1-7. Waterborne Viruses of Concern to Human Health and Their Associated Diseases Table 1-8. Waterborne Helminths of Concern to Human Health and Their Associated Diseases Table 1-9. Waterborne Fungi of Concern to Human Health and Their Associated Diseases Table Primary Contact Recreational Water Quality Criteria for Microorganisms Table Key Points of Epidemiological Studies Table 2-1. Summary of Detection Methods for Bacteria Table 2-2. Summary of Detection Methods for Viruses Table 2-3. Summary of Detection Methods for Cryptosporidium and Giardia Table 3-1. Distinction between a Treatment Technology and a BMP for Pathogen Control Table 3-2. Cost Projection of Disinfection to be Implemented at the Spring Creek Facility Table 3-3. Stormwater BMP Effectiveness Data Table 3-4. Results of Wetlands Effectiveness Studies on Secondary Sewage Effluent at Pima County, AZ Constructed Ecosystem Research Facility ix

10 Figures Figure 1-1. Microbial Pathogens Attributed to Cases of Illness from Exposure to U.S. Surface Drinking Water Sources, Figure 1-2. Microbial Pathogens Attributed to Outbreaks of Illness from Exposure to U.S. Surface Drinking Water Sources, Figure 3-1. Fecal Coliform % Removal Efficiency by BMP Type x

11 Acknowledgments This report is a compilation of literature, reviewed, analyzed, and submitted by the U.S. EPA s National Risk Management Research Laboratory, Water Supply and Water Resources Division, Urban Watershed Management Branch (UWMB), Edison, NJ. This report contributes to EPA s long term goal to provide the tools to restore and protect aquatic systems and to forecast the ecological, economic, and human health outcomes of alternative solutions. The report preparation commenced in September 2002, and the report was completed in September Annual performance requirements are fulfilled upon report completion. Editor for this literature review is Joyce Perdek. Reviewers, who provided instrumental comments, include Cecil Lue-Hing President of Environmental and Water Resources Institute, Sydney Munger and Charles Wisdom of Parametrix, Inc. (Kirkland, WA), Peter Swenson of U.S. EPA Region 5, and Stephen Schaub and Don Waye of U.S. EPA Office of Water. In addition several members of the UWMB provided valuable review, advice, and input. These reviewers are Michael Borst, Carolyn Esposito, Chi-Yuan Fan, Richard Field, Bethany Madge, Thomas O Connor, Ariamalar Selvakumar, Daniel Sullivan, and Anthony Tafuri. Judy Norinsky of the Environmental Careers Organization served as technical editor. The authors also wish to thank fellow EPA researchers Mark Meckes, Frank Schaefer, and Joyce Simpson who offered their microbiological expertise to assist in preparation of this and other UWMB pathogen projects. xi

12 Chapter One Regulating Waterborne Pathogens 1.1 Introduction Pathogens, disease causing microorganisms, are a major concern for managers of water resources. Once in a water body, pathogens infect humans through contaminated fish and shellfish, skin contact, or ingestion of water. Protection from pathogen contamination is most important for waters designated for (1) recreation, (2) public water supplies, (3) aquifer protection, and (4) protection and propagation of fish, shellfish, and wildlife. These uses are rigorously dealt with in Section 303(c) of the Clean Water Act (CWA) (U.S. EPA, 2001a). Data on U.S. water bodies in violation of microbiological ambient water quality standards, established by the states, for the years 1999 and 2000 are presented in Table 1-1. The Maximum Contaminant Level Goals (MCLGs) established under the Safe Drinking Water Act are zero for all pathogens. These goals conform to the position of the World Health Organization (WHO) (1993):...there is no tolerable lower limit for pathogens, and water intended for consumption, for preparing food and drink, or for personal hygiene should thus contain no agents pathogenic for humans. The WHO estimates that 13 million people die from waterborne infections each year. The majority of these deaths occur in developing countries. However, in the U.S. approximately 900,000 cases of illnesses and 900 deaths occur each year as a result of microbial contamination of drinking water (Warrington, 2001a). A pathogen may be a bacterium, protozoan, virus, worm, or fungi. Generally, waterborne pathogens are in human and animal feces, and are deposited directly into water bodies or transported to water bodies by overland flow and/or subsurface water flow. Urban pathogens are transported by stormwater runoff, combined sewer and sanitary sewer overflows, and wastewater treatment plant effluents. Pathogenic microorganisms originate from many animal species in watersheds including wildlife, pets and companion animals, and agricultural animals. There is increasing interest in the potential for molecular fingerprinting methods, also known as microbial source tracking techniques, for identification of pathogen sources (Simpson et al., 2002). The majority of large scale pathogenic waterborne outbreaks in the past have been attributed to human contamination or inadequacies at water treatment plants. The most current waterborne 1-1

13 Table 1-1. U.S. Microbial Water Quality Assessments Summary 1999 and 2000 Rivers and Streams 19% of U.S. river and stream miles assessed 39% of assessed river and stream miles impaired Pathogens (bacteria) are leading cause of impairment Agriculture is the primary source of impairment Ocean Shorelines 6% of U.S. ocean shoreline miles assessed 14% of assessed shoreline miles impaired Pathogens (bacteria) are leading cause of impairment Urban runoff/storm sewers are primary source of impairment Great Lakes Shorelines 92% of U.S. Great Lakes shoreline miles assessed 78% of assessed shoreline miles impaired Pathogens (bacteria) are third leading cause of impairment Contaminated sediments are the primary source of impairment Estuaries 36% of U.S. estuarine square miles assessed 51% of assessed estuaries square miles impaired Pathogens (bacteria) are fourth leading cause of impairment Municipal point sources are primary source of impairment Lakes, Reservoirs, and Ponds 43% of U.S. lake, pond and reservoir acres assessed 45% of assessed lake acres impaired Pathogen (bacteria) are not a leading cause of impairment Agriculture is the primary source of impairment U.S. EPA, 2002a outbreaks upon contact with contaminated recreational water bodies are attributed to human fecal contamination or sewage (Levy et al., 1998; Upton, 1999). Rosen (2000) identified the following characteristics of waterborne pathogens of concern: 1. The organisms are shed into the environment in high numbers, or they are highly infectious to humans at low doses. 2. The organism can survive and remain infectious in the environment for long periods or they are highly resistant to water treatment. 3. Some types of bacterial pathogens can multiply outside of a host under favorable environmental conditions. Identifying the microorganisms causing water quality standard violations or waterborne disease outbreaks is the first step in managing watershed microbial contamination. Emerging 1-2

14 pathogens are disease agents that were unknown or not associated with water 10 to 20 years ago. Many emerging pathogens are not new, but are only now associated with waterborne disease. These novel disease-bearing microbes are engendered by a complex mixture including social, political, economic, ecological, and technological factors, and are prone to arise among an immuno-compromised population. Cryptosporidium parvum, Legionella, and E. coli O157:H7 are preeminent waterborne emerging pathogens (Cliver, 2000; U.S. EPA, 2001b). For U.S. water bodies not meeting state-established water quality standards for microbial contaminants, a Total Maximum Daily Load (TMDL) must be developed. A TMDL is defined as the maximum amount of a pollutant that a water body can receive and still meet the water quality standard, and an allocation of that amount to the pollutant's sources. Usually, the TMDL target level will be the numeric water quality criteria maximum for the microorganism for which the standard was exceeded. In some cases, when the water quality standard does not sufficiently reflect the use impairment, it is appropriate to develop and meet an alternative standard. Examples of use impairments include waterborne disease outbreaks, degraded fisheries, and restrictions on using the water body for the desired use of primary contact recreation. For these situations, U.S. EPA recommends using a supplemental microorganism to provide additional means for measuring attainment of designated or existing uses (U.S. EPA, 2001a). This chapter provides information to support the first two steps of the seven step TMDL process below. The information is also useful to support investigations of waterborne disease outbreaks and management of water bodies not subject to the TMDL process. TMDL Process 1. Problem Identification 2. Identification of Water Quality Indicators and Target Values 3. Source Assessment 4. Linkage Between Water Quality Targets and Pollutant Sources 5. Allocations 6. Follow-up Monitoring and Evaluation 7. Assembling the TMDL The problem identification step s objective (U.S. EPA, 2001a) is to: Identify background information and establish a strategy for specific 303(d) listed waters that will guide the overall TMDL development process. Summarize the pathogen-related impairment(s), geographic setting and scale, pollutant sources of concern, and other information needed to guide the overall TMDL development process and provide a preliminary assessment of the complexity of the TMDL (what approaches are justified and where resources should be focused). The identification of water quality indicators and target values objective (U.S. EPA, 2001a) is to: 1-3

15 Identify numeric or measurable indicators and target values that can be used to evaluate the TMDL and the restoration of water quality in the listed waterbody. The information in this chapter on applicable numeric water quality standards, alternative standards to support designated use, and evaluation of indicator microorganisms as water quality criteria should be understood when undertaking problem identification in the TMDL process. Information on pathogens causing waterborne disease outbreaks is provided as background and may be most useful in situations where outbreaks occur. 1.2 Health Effects This section discusses waterborne disease outbreaks and known waterborne pathogens. The link between wet weather flow and outbreaks, and the data on pathogen related outbreaks reported in the U.S. is presented. The following are detailed descriptions of bacteria, protozoa, viruses, helminth worms, and fungi Waterborne Disease Outbreaks Discharges of stormwater runoff, combined sewer overflows (CSOs), and sanitary sewer overflows (SSOs) (all known as wet weather flows) to receiving waters create the potential for disease outbreaks. Through climate and epidemiological records, Rose et al. (2000) demonstrated a potential correlation between extreme precipitation events (the highest 20 percent of total intensity over a 20-year period) and waterborne disease outbreaks. The authors found that statistically significant relationships could be identified between these precipitation events and waterborne disease outbreaks due to contact with water from both surface and ground water sources, although the relationship was much stronger for surface water outbreaks. Swimming in contaminated marine and fresh recreational waters may result in a broad spectrum of illnesses. Water bodies may be contaminated and continuously re-contaminated, particularly if heavily used by people. For most pathogens warmer waters are more of a risk and are pathogen reservoirs. Lack of flow and water stagnation allows pathogens to accumulate. Swimming-associated disease outbreaks in natural U.S. waters between 1986 and 2000 due to microorganisms are listed in Table 1-2. Exposure pathways of pathogens in recreational waters are dermal contact, ingestion and inhalation resulting in skin, ear, eye, gastrointestinal, and respiratory illnesses. Few studies other than those related to outbreaks have been conducted to determine the etiological agents related to swimming associated illnesses (WHO, 1999). One large-scale epidemiological study of swimmers in marine waters receiving stormwater runoff involved interviewing over 15,000 individuals (Haile et al., 1999). Researchers reported higher risks of upper respiratory and gastrointestinal infections for swimmers who swam (1) near stormdrain outfalls, (2) in waters with high levels of single bacterial indicators and a low ratio of total to fecal coliforms, and (3) in waters where enteric (intestinal) viruses were detected. These 1-4

16 positive associations with adverse health effects indicate an increased risk of illness associated with swimming in ocean water subject to untreated urban stormwater runoff. More than 1% of the swimmers who swam in front of the outfalls were affected by fevers, chills, ear discharges, vomiting, and coughing. Some studies attempting to link health effects to pathogen sources yield inconclusive results. For example, seventeen E. coli O157:H7 cases led Perez Guzzi et al. (2000) to investigate potential contamination from CSOs on California s Mar del Plata beaches. Their investigation detected no E. coli O157:H7, although other strains of E. coli were detected in 75% of the samples. None of the 98 strains detected in the outfalls were the strains that were known to cause human illness. Pathogens present in a watershed can enter the drinking water supply through stormwater runoff, combined and sanitary sewer overflows, and illicit sanitary wastewater cross connections into storm drains. Exposure pathways for pathogens in drinking water include ingestion, dermal contact, and inhalation. Failures in water treatment systems, including the inability of disinfection procedures to inactivate all pathogens, allow these microorganisms to remain in finished water. Table 1-3 summarizes the effectiveness of water treatment processes on waterborne pathogens. Giardia and Cryptosporidium caused the largest number of drinking water-associated cases and outbreaks reported to the Center for Disease Control (CDC) from (Table 1-4 and Figures 1-1,1-2). Although the drinking water treatment system met state turbidity effluent requirements at all times immediately prior to and during the Milwaukee Cryptosporidium outbreak in 1993, an assessment of the problem by a U.S. EPA investigative team identified a potential link between high turbidity levels in the influent and the occurrence of Cryptosporidium (Fox and Lytle, 1996). The American Society for Microbiology (ASM) reports that outbreaks are associated with pathogen contamination of municipal water systems that operate according to government standards, like Milwaukee. This indicates current methodologies are unable to fully detect treatment system failures and water quality that will adversely affect public health (Warrington, 2001a). Pathogen survival in aquatic environments affects their ability to cause illness. Many environmental stressors effect survival, most notably sunlight intensity. Intense ultraviolet sunlight over surface waters enhances bacterial die-off, therefore limiting serious bacterial impacts (Chamberlin et. al., 1978). Bacteria in turbid waters and bottom sediments are not as susceptible to sunlight as surface water microorganisms, and therefore survive longer. Protozoa and viruses survive UV radiation better than bacteria (Johnson et. al., 1997). Pathogen survival is also dependent on water temperature. Increased water temperature decreases the survival of bacteria in surface water. Reduced cell metabolism in cold water enhances bacteria survival (Terzieva et al., 1991). Protozoa and viral survival is also increased in cold water (LeChevallier et al., 1991; Wait et al., 2000). Salinity (Johnson et al., 1997), competition and predation (Rozen et al., 2001), and nutrient supply (Gauthier et al., 1989) are additional environmental factors influencing die-off. Microbial survival is dependent on a combination of the above factors. U.S. EPA compiled die-off rates of microbial indicators and pathogens in Table 6-1 of Protocol for Developing Pathogen TMDLs (U.S. EPA, 2001a). 1-5

17 Table 1-2. Outbreaks Associated with U.S. Natural Recreational Waters Etiological Agent Cases# % of Cases Outbreaks* % of Outbreaks AGI** Shigella spp Naegleria fowleri E. coli O157:H Schistosoma spp Cryptosporidium parvum Norwalk-like Giardia lamblia Leptospira E. coli O121:H unknown Adenovirus TOTAL # A case is defined as a disease occurrence from an etiological agent. * An outbreak is defined as 1) greater than or equal to 2 persons experiencing a similar illness after contacting the recreational water and 2) epidemiologic evidence that implicates the water as the probable source of the illness. ** Acute gastrointestinal illness of unknown etiology. Barwick et al., 2000; CDC and U.S. EPA, 1993; Herwaldt et al., 1992; Kramer et al., 1996; Lee et al., 2002; Levine et al., 1990; and Levy et al.,

18 Table 1-3. Water Treatment Effectiveness on Pathogens Pathogen Type Bacteria Protozoa Viruses Helminths Fungus Water Treatment and Effectiveness Normal disinfection procedures using chlorine are sufficient to kill bacteria Multi-barrier approach including conventional physical processes of sedimentation, coagulation and filtration can remove 99% or better of most protozoa. Chemical disinfection effectiveness is minimal. Conventional physicochemical processes of sedimentation, coagulation, filtration and chlorination effectively removes better than 99.99% of enteric viruses. The exception is the Norwalk Virus which is resistant to chlorine disinfection and relies on physical processes. Conventional physicochemical processes of sedimentation, coagulation, filtration and chlorination effectively eliminate helminths. Sub-micron filtration removes fungi. Fungi are immune to normal levels of water chlorination but are inactivated by UV or destroyed by ozone. AWWA, Table 1-4. Outbreaks Associated with Drinking Water from U.S. Surface Sources Etiological Agent Cases# % of Cases Outbreaks* % of Outbreaks Campylobacter Cryptosporidium parvum Cyanobacteria like Giardia lamblia Shigella sonnei Ca. Jejuni E. coli O157:H SRSV AGI** TOTAL # A case is defined as a disease occurrence from an etiological agent. * An outbreak is defined as 1) greater than or equal to 2 persons experiencing a similar illness ** Acute gastrointestinal illness of unknown etiology. Barwick et al., 2000; CDC and U.S. EPA, 1993; Herwaldt et al., 1992; Kramer et al., 1996; Lee et al., 2002; Levine et al., 1990; and Levy et al.,

19 Figure 1-1. Microbial Pathogens Attributed to Cases of Illness from Exposure to U.S. Surface Drinking Water Sources, Tota l Number of Cases = 437,082. Cryptosporidi um parvum ( 95.9% ) Acute Gastrointest inal Illness of Unknown Etiology ( AGI) ( 2.8% ) Gi ardia lambli a (0.8%) Other ( 0.5% ) Figure 1-2. Microbial Pathogens Attributed to Outbreaks of Illness from Exposure to U.S. Surface Drinking Water Sources, Total 48 Outbreaks. Giardia lamblia ( 41.7% ) AGI (31.2%) Cryptosporidi um parvum ( 10.4% ) E. co li O157:H7 (6.2%) Ca. Jejuni ( 2.1% ) Campyl obacter (2.1%) Cyanobacteria-li ke (2.1%) Shigella sonnei ( 2.1% ) Small Round Structured Virus (SRSV) (2.1%) Barwick et al., 2000; CDC and U.S. EPA, 1993; Herwaldt et al., 1992; Kramer et al., 1996; Lee et al., 2002;Levine et al., 1990; and Levy et al.,

20 1.2.2 Pathogenic Bacteria of Concern Bacteria are unicellular microorganisms that exist as either free living organisms or as parasites. Bacteria play a fundamental role in the decomposition and stabilization of organic matter in nature and in biological sewage treatment processes. Bacteria range in size from 0.4 to 14 micrometers or microns (µm) in length and 0.2 to 1.2 µm in width. Many types of enteric pathogenic bacteria occur in water supplies and in wastewater. The U.S. EPA (2000a; 2002a) assessed bacteria as one of the leading causes of impairments to surface waters. With increasing demands on water resources, the potential for contamination of surface and groundwater by pathogenic enteric bacteria is expected to rise resulting in an increase in waterborne disease outbreaks. Gastrointestinal illness, i.e., diarrhea, nausea, and cramps, is a common symptom of infections caused by enteric waterborne bacteria. Some pathogens spread through the body from the intestinal mucosa and cause systemic infections known as enteric fevers. One example of this is typhoid fever. Chlorine disinfection is highly effective for most bacteria (AWWA, 1999). Enteric bacteria tend to die off faster than strains indigenous to surface and groundwaters because they are unable to compete successfully with natural microflora for low nutrient concentrations (Sinclair and Alexander, 1984). However, some bacteria are able to adapt to low nutrient concentrations by transforming to a viable but nonculturable (VBNC) state (Wang and Doyle, 1998; Huq and Colwell, 1996). VBNC bacteria maintain metabolic activity and infectiousness, but do not grow and multiply on culture plates, making them difficult to detect with conventional methods. Enteric pathogenic bacteria transmitted by water and wastewater include Campylobacter, E.coli O157:H7, Leptospira, Salmonella, Shigella, Vibrio cholerae, and Yersinia entercolitica. Legionella pneumophilia, while not enteric, is a pathogenic bacteria distributed in the aquatic environment. Waterborne pathogenic bacteria of concern and their associated diseases are presented in Table Campylobacter Campylobacters of concern to the water industry are the thermophilic group. They cause a variety of diseases in humans, principally acute diarrhea preceded by flu-like illness. Campylobacter enteritis is principally a zoonotic disease, communicated from lower animals to man under natural conditions. These bacteria are harbored in the intestines of domestic and wild animals, particularly birds. Indirect transmission by contaminated water and food is the most common infection mode. Campylobacter bacteria are killed by cooking procedures. Campylobacter is now recognized as the cause of a common enteric bacterial infection in the U.S. Over 21 cases for each 100,000 persons in the U.S. population (approximately 57,000 cases) are diagnosed each year (MMWR, 1999). Campylobacters are not found in water in the absence of E. coli (AWWA, 1999). 1-9

21 Table 1-5. Waterborne Bacteria of Concern to Human Health and Their Associated Diseases Bacteria Source Disease Effects Campylobacter Bird feces Diarrhea Acute diarrhea Escherichia coli O157:H7 (enteropathogenic) Cattle feces Gastroenteritis Vomiting, diarrhea Legionella pneumophilia Aquatic environments Legionellosis Acute respiratory illness Leptospira (150 spp.) Urine of dogs, livestock, wild animals Leptospirosis Jaundice, fever (Weil s disease) Salmonella typhi Domestic and wild animal feces Typhoid fever High fever, diarrhea, ulceration of small intestine Salmonella (~ 1700 spp.) Domestic and wild animal feces Salmonellosis Diarrhea, dehydration Shigella (4 spp.) Human feces Shigellosis Bacillary dysentery Vibrio cholerae Asymptomatic human feces Cholera Extremely heavy diarrhea, dehydration Yersinia entercolitica Animal feces Yersinosis Diarrhea Metcalf and Eddy, E. Coli O157:H7 E.coli O157:H7 is a pathogenic strain of Escherichia coli belonging to the group enterohemorrhagic E. coli. Human infection causes severe diarrhea and abdominal cramps. In young children (under five years old) and the elderly, complications leading to life threatening kidney failure can result (U.S. EPA, 2002b). The reservoir of this pathogen is primarily cattle. This specific strain is an emerging cause of waterborne and foodborne illness. Fecally contaminated water has been linked to recreational and drinking water outbreaks. An estimated 73,000 cases of infection and 61 deaths occur in the U.S. annually (CDC, 2001a). E. coli O157:H7 was the responsible agent in the Cabool, MO disease outbreak that killed four people, hospitalized 32 and caused diarrhea and other problems in 243 people (Geldreich et al., 1992). It is believed that breaks in drinking water mains resulted in low water pressure that allowed contamination from nearby SSOs to enter the drinking water system. In 1999 this pathogen was also responsible for the disease outbreak at a Washington County, NY fair due to contaminated drinking water. Of the 781 people identified with illnesses related to this outbreak, 127 cases of E. coli O157:H7 were confirmed by culture (Safefood News, 2000). 1-10

22 U.S. public water systems must notify homeowners if the water is unsafe. Private well owners should have their well tested periodically. Typically the well is tested for total coliform. If the test is positive, the water is then tested for E. coli. If the E. coli is positive, the water should not be consumed for drinking. U.S. EPA does not believe it is necessary for an owner of a private well to test specifically for E. coli O157:H7 under normal circumstances because the test is expensive and many labs do not have the expertise to perform this test (AWWA, 1999) Legionella pneumophilia Legionella is ubiquitous in the environment. The disease, legionellosis, is a severe respiratory illness characterized by pneumonia. It is found typically in surface waters at concentrations of per liter and is now recognized as part of the natural environment (Fliermans et al., 1981). It has also proliferated in artificial environments such as cooling towers, evaporative condensers, whirlpools, and hot water tanks. These environments act as amplifiers or disseminators of legionella pneumophilia. In the U.S., 17,000 to 23,000 cases a year are estimated. The largest outbreak occurred in Philadelphia, PA in 1976, where 220 cases and 34 deaths were reported, and the source is unknown. Most outbreaks since 1976 have been linked with hospital water distribution systems (AWWA, 1999) Leptospira Leptospira are spiral shaped bacteria. The induced disease, Leptospirosis or Weil s disease, first described in 1886, produces fever, headache, chills, malaise, vomiting, and occasionally meningitis. This bacteria is transmitted through the urine of dogs, livestock, and wild animals, and can contaminate natural water bodies, which then serve as sources of the infection. Dogs are the major source for human infections. A vaccine is available for dogs but not for humans. Between 100 and 200 documented cases per year occur in the U.S. (CDC, 2001a). In the summer of 1998, 110 athletes competing in a triathlon in Illinois were diagnosed with leptospirosis, and 23 needed hospital care. The outbreak was traced to Lake Springfield (MMID, 1999) Salmonella Salmonella is a group of over 1,700 types of bacteria. There are three distinguishable forms of salmonellosis, including gastroenteritis, enteric fever, and septicemia (characterized by chills, fever, anorexia or loss of appetite) in humans. Gastroenteritis is characterized by diarrhea, fever and abdominal fever. Enteric fever caused by Salmonella typhi is prolonged, lasting from 7 to 14 days. Salmonella septicemia is characterized by chills, fever, anorexia, and viable bacteria circulating in the blood known as bacteremia. Domestic and wild animals, and humans are possible sources of Salmonella. Waterborne outbreaks of salmonellosis are normally classified as acute gastrointestinal illness of unknown etiology. These outbreaks in the U.S. are associated with poor quality source water and inadequate treatment and/or contamination of distribution systems. In the U.S., over 40,000 cases of salmonellosis are reported each year, with the incidence being about 17 cases per 100,000 people (CDC, 2000; CDC, 2001b). The largest 1-11

23 known waterborne incidence of this disease occurred in 1965 in Riverside, CA and affected 18,000 people. The water supply was blamed, but the source of contamination was never determined (AWWA, 1999) Shigella Shigella is a genus of bacteria that causes sudden and severe gastroenteritis in humans, known as shigellosis. Infected humans are the only significant reservoir. Waterborne outbreaks result from fecal contamination of nonchlorinated private and noncommunity water supplies. Septic tank contamination of wells, or cross-connections between wastewater and potable water lines are commonly implicated in drinking water outbreaks. Recreational exposure to fecally contaminated swimming areas is also prevalent (AWWA, 1999). Approximately 25,000 confirmed cases of shigellosis from all sources are reported in the U.S. each year. However, many cases go undiagnosed, and 450,000 cases are estimated annually (Baer et al., 1999) Vibrio cholerae Over 130 groups of Vibrio cholerae have been studied. This bacteria is responsible for the illness cholera, which produces acute diarrhea, dehydration, vomiting, shock, and possibly death. Cholera is typically spread by poor sanitation. The most important reservoirs are asymptomatic human carriers and diseased people who shed this bacteria in their feces. Sporadic cases occur when shellfish are harvested and eaten raw from fecally polluted waters. The excellent sanitation facilities in the U.S. are responsible for the near eradication of epidemic cholera here. Cholera was reported in South America from 1991 to 1995, where it grew to epidemic levels (1,099,882 cases and 10,453 deaths). Since this outbreak, most cases of cholera in the U.S. have occurred among persons traveling from cholera-affected areas (CDC, 1995; U.S. FDA, 2003a). Vibrio cholerae can also be present naturally in the environment, and natural waters can be a source of this bacteria. This presence in the environment has been demonstrated in the U.S. and Australia, where toxigenic strains survived in aquatic environments for years in the total absence of fecal contamination (AWWA, 1999). Of particular concern is their presence in warm, shallow, Gulf Coast waters, where oysters, as filter-feeders, concentrate these Vibrio spp. organisms in their tissues (Hopkins et al., 1997) Yersinia entercolitica Yersinia entercolitica is a facultative anaerobe (lives under either aerobic or anaerobic conditions). This bacteria causes gastroenteritis, usually in children under seven years old, characterized by fever, diarrhea, abdominal cramps, and sometimes vomiting. It is mainly recognized as a foodborne pathogen, but may be found in sewage and polluted waters, and can enter drinking water via pollution from these sources. Essentially, it is found where one might encounter coliform organisms. However, Yersinia entercolitica is able to survive for longer periods of time in aquatic environments (survival has been shown to grow at low temperatures and survive for 18 months at 4 C) than fecal coliform. Therefore, this organism can be present when the coliform indicator organisms are not (AWWA, 1997). 1-12

24 1.2.3 Pathogenic Protozoa of Concern Protozoa are one-celled animals varying in size from 2 to 100 µm. They live in many animals and survive in cysts (protective shells) when outside of an organism. Protozoa reproduce rapidly inside a host organism; therefore, ingestion of only a few by a human causes disease. Once in water, protozoa can survive for several weeks, even longer if frozen in ice. The waterborne pathogenic protozoans of greatest concern in countries with temperate climates are Cryptosporidium and Giardia. Oocysts of Cryptosporidium and cysts of Giardia occur in surface water, where their concentration is related to the level of fecal pollution or human waste present. Oocysts and cysts are both very persistent in water and are very resistant to disinfectants commonly used in drinking water treatment. In industrialized countries, outbreaks of cryptosporidiosis and giardiasis are due to oocysts and cysts entering the drinking water because of treatment failure, contamination of the source water, and/or leakage into the distribution system (WHO, 1993). Recently there is a growing concern regarding Cyclospora, especially in nonindustrialized countries. Entamoeba histolytica and Naegleria fowleri are additional watertransmitted intestinal parasites of concern worldwide due to their serious consequences. Table 1 6 lists waterborne pathogenic protozoa of concern and their associated diseases Cryptosporidium Cryptosporidium induces the disease cryptosporidiosis, which is capable of producing unpleasant gastric and diarrheal illness (Rose, 1997). The parasite s transmittable stage is a 4 to 6 :m diameter spherical shaped oocyst which contains a hardy thick wall. The oocyst is spread through the feces of infected humans and animals, including mammals, birds, reptiles, and fish. Cryptosporidium is frequently waterborne in nature and infections have occurred through contact with contaminated drinking water supplies, as well as zoonosis (animal person contact), contaminated food, contaminated swimming pools, and other recreational waters. Oocysts may be present in animal slurry spread on farmland as fertilizer. Consequently, runoff from rain carries oocysts into streams, lakes, and other reservoirs. Sewage is another source. The infective dose varies from less than 30 oocysts to as many as one million oocysts. There are six species of Cryptosporidium, but only one species, Cryptosporidium parvum, found in animals, is known to infect humans. Both known Cryptosporidium parvum genotypes can cause infections in human beings. Genotype 1 has (so far) been found almost exclusively in humans, and is more virulent than Genotype 2, which is found in a wide variety of animals, including humans (Xiao et al., 2001). 1-13

25 Table 1-6. Waterborne Protozoans of Concern to Human Health and Their Associated Diseases Protozoan Source Disease Effects Cryptosporidium Human, animal, and bird feces Cryptosporidiosis Diarrhea, death in susceptible populations Cyclospora Human feces Cyclosporiasis Diarrhea Entamoeba histolytica Human feces Amebiasis (amoebic dysentery) Prolonged diarrhea with bleeding, abscesses of the liver and small intestine Giardia lamblia Human, animal, and bird feces Giardiasis Mild to severe diarrhea, nausea, indigestion Naegleria fowleri Bird and aquatic mammal feces Meningoencephalitis (PAM) Inflammation of brain and meninges Fout, 2002; Metcalf and Eddy, 1991 States et al. (1997) found Cryptosporidium in treated sewage and CSO from an area incorporating dairy farms. In an investigation of CSO in urban areas, Arnone et al. (2003) reported essentially no Cryptosporidium in the two cities and three outfalls investigated. The largest recorded outbreak of cryptosporidiosis occurred in Milwaukee in 1993, where an estimated 403,000 people were infected, and approximately 50 to 100 area residents with compromised immune systems died prematurely (Blair, 1994; Hoxie et al., 1996). Another significant cryptosporidiosis outbreak occurred in Las Vegas in 1994, and infected 78 people, most of whom had human immunodeficiency virus (HIV) infections (Roefer et al., 1996). At present nothing other than the body s defense system can treat cryptosporidiosis. Cryptosporidium, therefore, poses some alarming public health problems, particularly for people with weakened immune systems, especially acquired immunodeficiency syndrome (AIDS) patients. These patients are prone to severe and protracted diarrhea which can persist for months with considerable weight loss and mortality (Gerba et al., 1996; Rose, 1997). A well-operated drinking water plant can physically remove only 99% of oocysts from infected raw waters. Traditional processes such as coagulation, clarification, and filtration remain the best defense against this parasite entering the water supplies. Encystment can protect protozoa from drinking water disinfection efforts (Frey et al., 1998). U.S. EPA regulations addressing this contaminant in drinking water supplies are discussed in U.S. EPA (2001c) and Chapter

26 Cyclospora Cyclospora, species Cyclospora cayetanensis, are 8 to 10 µm in size. Disease symptoms mimic those caused by cryptosporidiosis, including mild nausea, anorexia, abdominal cramping, and diarrhea. Humans are the only natural host. Noninfectious Cyclospora oocysts are passed in the feces of infected individuals. The unsporulated oocysts are usually transmitted via water and require 7 to 15 days to sporulate and become infectious. Consumption of untreated water has led to infection. During the spring of 1996 approximately 850 cases of cyclosporiasis were confirmed in the U.S. and Canada. The infection lasts up to seven weeks. Symptoms typically mimic those of cryptosporidiosis (AWWA, 1999) Giardia lamblia Giardia lamblia, also known as Giardia duodenalis and Giardia intestinalis, is the most common cause of protozoa infection in humans. Sometimes referred to as beaver fever, hiker s disease, or camper s disease, Giardia infection, or giardiasis, causes abdominal cramps, diarrhea, and bloating. Giardia is found in humans, dogs, cats, pigs, sheep, beavers, and many other domestic animals, as well as birds. Humans are usually infected by one particular species of the many that exist, Giardia lamblia, which also causes infections in domestic and wild animals. There are six strains of Giardia lamblia. The strain type is not consistently associated with disease severity. Different individuals show various degrees of symptoms when infected with the same strain (U.S. FDA, 2003b). The infection is transmitted by tiny spores or egg-like cells called cysts measuring 9 to 12 µm in length. Watershed runoff and untreated and treated sewage transport Giardia to lakes, rivers and other receiving water bodies. There is an increase in Giardia infections during and after heavy rainfalls. Due to its thick wall, the Giardia cyst can survive weeks or months in fresh water, although it is less hardy than the Cryptosporidium oocyst (Rosen, 2000). There have been over 20 outbreaks of waterborne Giardia in the U.S. from recreational and surface drinking water contact between 1986 and 2000 (Barwick et al., 2000; CDC and U.S. EPA, 1993; Herwaldt et al., 1992; Kramer et al., 1996; Lee et al., 2002; Levine et al., 1990; and Levy et al., 1998). The infective dose for Giardia cysts may be between 10 and one million viable cysts depending on the immune system of the host. Giardiasis can be treated with drugs, including metronidazola, furazolidone, trinidazole, and paromomycin. Therefore, giardiasis is not regarded as a fatal disease. Giardia infection occurs due to its reproduction in the digestive system and attachment to the small intestine. After ingestion, the cyst passes through the stomach to the duodenum where it hatches and produces two trophozoites, feeding configuration of the parasite. The trophozoites measure 12 to 18 :m in length and adhere to the surface of the mucous membranes of the small intestine. The trophozoites damage the membrane and inhibit adsorption of nutrients that cause the disease giardiasis. The trophozoites then form cysts as they pass along the small intestine and eventually pass out with the feces (Rosen, 2000). Many individuals are asymptomatically affected by Giardia, as demonstrated by a CDC study of a population who consumed water heavily contaminated with Giardia due to malfunction in the 1-15